code: def test_validate(self) -> None:
      val_mha = self.mv[type(self.mha)](self.mha)
      self.assertEqual(len(val_mha), 1)
      self.assertTrue(isinstance(val_mha[0], ShouldReplaceModuleError))
  
file_path: opacus/opacus/tests/validators/multihead_attention_test.py
imports: import unittest
  import torch.nn
  from opacus.layers import DPMultiheadAttention
  from opacus.utils.module_utils import are_state_dict_equal
  from opacus.validators.errors import ShouldReplaceModuleError
  from opacus.validators.module_validator import ModuleValidator
label_desc: Use image node_id 2 for calling the MultiheadAttentionValidator_test obj's underlying member method code with example usage: obj.test_validate() without return types